From Longman Dictionary of Contemporary Englishboil over phrasal verb1 DFCif a liquid boils over when it is heated, it rises and flows over the side of the container The milk was boiling over on the stove behind her.2 ANGRYif a situation or an emotion boils over, the people involved stop being calm All the bitterness of the last two years seemed to boil over. into Anger eventually boils over into words that are later regretted. → boil→ See Verb table
Examples from the Corpus
boil into• The game had been brutal, the aggression often boiling over into mini-battles on the pitch between opposing players. 